The partial oxidation process is a well known process for converting liquid hydrocarbonaceous and solid carbonaceous fuels into synthesis gas, reducing gas, and fuel gas i.e. gaseous mixtures comprising H.sub.2 +CO. See coassigned U.S. Pat. Nos. 3,988,609 and 4,251,228 for example, which are incorporated herein by reference.
Ash-containing heavy liquid hydrocarbonaceous fuels i.e. coal derived oil, and ash-containing solid carbonaceous fuels i.e. coal are desirable low-cost feedstocks for the partial oxidation process. However, when these fuels are used, the hot effluent gas stream from the reaction zone contains entrained molten slag. In some cases some of the molten slag entrained in the effluent gas stream may deposit on the inside metal surfaces of a gas transfer line or a gas transfer line and a convective cooler connected thereto and located downstream of the reaction zone. Over a period of time, the build-up of these deposits, may lead to reduced efficiency and/or operating difficulties. This problem and others may be avoided by the subject process thereby resulting in reduced downtime and lower maintenance costs.